This is the map from the first mission in the Colonial Marines expansion for the Alien RPG game by Free League Publishing. I appreciate their maps, but the green on black maps they provide can be hard on the eyes, particularly near the end of a longer game session.
This map has retained its scale to the best of my ability.
I also made some minor logical changes to it (for instance, swapping the rail gun magazine with the MedBay to put the rail gun magazine right next to the rail gun).